#include "unp.h"

int main(int argc, char **argv) {
	int i, maxi, maxfd, listenfd, connfd, sockfd;
	int nready, client[FD_SETSIZE];
	ssize_t n;
	fd_set rset, allset;
	char buf[MAXLINE];
	socklen_t clilen;
	struct sockaddr_in cliaddr, servaddr;
	listenfd = Socket(AF_INET, SOCK_STREAM, 0);
	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	servaddr.sin_port = htons(9999);
	Bind(listenfd, (SA*)&servaddr, sizeof(servaddr));
	Listen(listenfd, LISTENQ);
	maxfd = listenfd;
	maxi = -1;
	for (i = 0; i < FD_SETSIZE; i++) {
		client[i] = -1;
	}
	FD_ZERO(&allset);
	FD_SET(listenfd, &allset);
	for (;;) {
		rset = allset;
		nready = Select(maxfd+1, &rset, NULL, NULL, NULL);
		if (FD_ISSET(listenfd, &rset)) {
			clilen = sizeof(cliaddr);
			connfd = Accept(listenfd, (SA*)&cliaddr, &clilen);
			for ( i = 0; i < FD_SETSIZE; i++) {
				if (client[i] < 0) {
					client[i] = connfd;
					break;
				}
			}
			if (i == FD_SETSIZE)
				err_quit("too many clients");
			FD_SET(connfd, &allset);
			if (connfd > maxfd)
				maxfd = connfd;
			if (i > maxi)
				maxi = i;
			if (--nready <= 0)
				continue;
		}

		for (i = 0; i <= maxi; i++) {
			if ((sockfd = client[i]) < 0)
				continue;
			if (FD_ISSET(sockfd, &rset)) {
				if ((n = Read(sockfd, buf, MAXLINE)) == 0) {
					Close(sockfd);
					FD_CLR(sockfd, &allset);
					client[i] = -1;
				} else {
					Writen(sockfd, buf, n);
				}
				if (--nready <= 0)
					break;
			}
		}
	}
}
